What Causes Vaginal Discharge Of Blood Tissue During Menstruation And Intercourse?

Had tubal cauterization done 5 years ago. Last month's cycle was late by about a week, heavy bleeding. This month's cycle was closer to on time, also heavy bleeding the first couple days (sounded like I was peeing once when I sat to pee). Blood bright red. Major cramping and lots of small blood clots. Cramping increased to contraction-like pain on second day, then I passed a very big blood clot (I felt it as it came out, and it splashed water everywhere when it landed in the toilet). I've been passing grape-like tissue for a couple weeks now but only noticeable during sex and my cycle. Could it be a delayed miscarriage? Also was nauseous and breasts were extremely tender to touch.